Ellipsograph.



PATENTED IEB. v25, 190e.

H. LOOYER.

ELLIPSOGRAPH.

APPLICATION FILED JUNI: 14,19o7.`

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WH: :v0/mls PETERS co.. wAsHlNdroN. o. c.

HENRY LOOYER, OFACHICAGO, ILLINOIS.

ELLIPSOGRAPH.

Specification of Letters Patent.

Patented Feb. 25, 1908.

Application filed .Tune 14.1907. Serial No. 378.953-

To all whom it ymay concern.'

Be it known that I, HENRY LOOYER, citizen of the United States, residing at Chicago, in the county of Cook and State of lllinois, have invented certain new and useful Improvements in Ellipsographs, of which the following is a specification.

My invention relates to mathematical instruments of precision and especially to the `class of drafting' or drawing appliances, referring particularly to apparatus designed for describing geometrical figures, and arranged expressly for delineating conic sections and allied curves.

Instruments for drawing irregular curves have been frequently constructed, but they are usually complicated in their mechanical construction and generally require special skill and experience in the art to enable the operator to manipulate them successfully and in addition to the fault of being cumbersome and unwieldly, their excessive cost has proved a bar to a widely extended use.

To construct oval or elliptical figures without the employment of a mechanical aid other than that of the ordinary drafting tools is a slow and unsatisfactory process, since the proper joining of the arbitrary curved segments, and the determination of the centers, when the curves are formed by means of an ordinary compass employing a plurality of centers, require great care and consume a proportionate length of time. The shifting of centers to accommodate the tool to the variations between the major and minor axes of ellipses becomes tedious when many iigures have to be laid out and inaccuracy is a frequent result.

rlhe paramount objects of my improvements are to produce an instrument adapted to describe elliptical and other irregular curves with accuracy and despatch ,1 to provide an. ellipsograph that can be readily applied to any point of the prepared surface upon which the figure is to be delineated, so that the location of the centers may be readily and easily determined and the governing points in the mechanical movements be rapidly shifted as occasion requires; and to supply strong and rigid supports that will afford a minimum obstruction to a proper view of the field of operation. l l

Further objects of my instrument are to provide an ellipsograph that can be adjusted. so as to enable the axes of ellipses and ovals to be drawn to any desired angle relative to a given base and to permit change of angle and dimensions Without shifting the position of the supporting members; and to afford means for changing the relation of some of the guiding elements to produce' a more compact form of instrument for the construction of certain classes of irregular curves, to furnish a simple and easily understood appliance adapted to the tracing of a large variety of both regular and irregular curves; to provide an instrument having few parts and so' designed that some of the members may be folded and other parts dissected to enable the entire instrument to be dismantled and placed in a small compass convenient for stowing in a suitable case. Since the instrument has 'few parts all designed and constructed on simple lines, the apparatus can be produced with a minimum outlay for special machinery and because of the economy thus possible in its manufacture, the complete instrument can be supplied at a moderate cost.

Another advantage lies in the mechanical design which will produce smooth and uniform movements, and as a large proportion of such movements are pivotal the lines Will be accurate and well defined.' A special feature is made of the graduated scales which are placed wherever they `may be required in use and will facilitate the speedy manipulation of the mechanism. The main point or focal center, to which the major part of the movements are related, is also the operating point and from this location the various motions are easily controlled.

l accomplish the above and other important results by the employment of an instru- Iment consisting, generally described, of

duplicate adjustable standards connected by parallel members upon one of which is mounted a sliding member which carries a tracing bar, and a directing arm having pivotal connection with a radial lever which revolves in a horizontal plane about the governing center, the latter being supported upon the other of said parallel connecting members, the latter having its continuity broken to permit of an angular and rectilinear movement of said governing center.

The principle of the instrument especially when arranged for tracing ellipses, ovals and circles, may be properly considered as related to that of the trammel, the master center being homologous with the intersection of the grooves of the trammel, and the reciprocating member is analogous to that trammel groove coincident with the major axis of an ellipse. The minoraxis groove of the trammel is omitted in this instrument, its function being performed by compound levers, ytheir combined length equalling the distance between the guide pins or blocks which travel in the trammel grooves, the pivotal connection between said levers being the analogue of the median ypoint between the pinsrof the trammel said point always describing a circular path about the intersection of the major and minor' axes, and in a 'similar way the said pivotal lconnection of ythe levers always moves in a circle about the governing or focal center. 4 The` preferred 'embodiment of my improved ellipsograph is fully illustrated in the accompanying ldrawing which forms a part of this specification, and in which Figure 1 is a side elevation of the instru` lment in the position adapted for universal work, Fig. 2 is a top plan view, showing in dotted position certain changes .in position of Athe 4adjustable members, and the location 'of the centers, lsame also dotted, when certain unusual curv'es are to be traced; Fig. 3 is an elevational view of'oneof the standards; Figs. 4, 5, and 6, are end, bottom and top views, respectively, of the graduated slide for the governing center; Fig. 7 is a side view fof the ypivot post for the sliding member,

showing the lrelation of the locking screw; Figs. 8 and 9 are, respectively, front and side views of the tracing stylus or pencil, and jFig. 1`() i sfa side view of a bow ypen which may 'be substituted for the pencil.

Referring to the drawing in detail, the

"numeral 15 indicatesduplicate upright posts orstandards each furnished with a base 16,

`so designed with laterally extending feet as to afford a stable foundation. Each upright is 'reduced below and received ina lsocket in the baseand may be adjusted vertically by a set screw I17. The posts 15 lare provided with'apertures 18 suited to receive parallel rectangular connecting members ,longitudinally adjustable therein and firmly fixed when adjusted by thumb screws 19.

The ,lower connecting member 2O is rectangular incross sectioniand continuous from standard to standard. The upper connecting member, differs from the lower'by'having its continuity `broken by the interposition of a slotted guiding bar 21, vhereinafter described, thus vbeing divided into 'two bars 22|, 23,`al`so rectangular. V This form of the structural tmembers affords special 'security against torsion and permits the movable or adjustable parts to be fixed in position with ease and certainty. The inner end of the bar 22 is secured to said guiding bar by a thumb screw 24 which can be released so that the connected parts may be swung horizontally as on a pivot. The inner end of the other member or bar 23, on the contrary is removably fixed in a bracket which is formed integral with the guide bar, by a thumb screw 26. By this arrangement, it will thus be seen, the standards 15 and the connecting .bars 20, 22, and 23, when ltheir respective thumb screws are tightened, form a rigid Vframework firmly secured to and supporting the said guide bar 21. The continuous rectangular bar20 carries a slide 27, which is adapted to reciprocate on said bar with a smooth yand easy movement when impelled in the manner to be described. This slide is composed of a body or sleeve 28 rectangular in cross section which surrounds the bar 20 and has a set screw 28a. Upon the side of said sleeve is an extension 29 through which passes a vertical pivot post 30. The head of Ythis post consists of a flat lplate which has a bearing upon the upper face of the extension, and vcarries a rectangular 'block 31. The lower end of vsaid post 30 extends below the extension where it is received in a box 32. The said box is adjustably secured to the post by a set screw 33 which has a conical end adapted to engage an annular groove 34 in said post. Through the lower end of thebox is passed a tracing rod or b'ar 35 adjustably secured by a thumb Upon said bar is slidably mounted a stylus holder 38 having a set screw 39 for fixing the holder at any point upon 'said bar. lIn order to make Iit possible lto bring the point of the stylus vertically beneath the center of rotation of said .post 30 the holder may be which will pass 'beneath the box 32 so that the axial linesfof the post and stylus will coincide. A bow pen 41 (Fig. 10) may be substituted for the stylus. The shank 42 of said pen is swiveled in a block 43 Aadapted to slide upon the tracing rod 35 and has a retaining cap 44 secured to the end ofthe shank by a set Screw 45. The axis of the pen is inclined to the horizontal lane as shown in Fig. 10 to bring thepointoflthepen vertically ybeneath the tracing bar, thus con ducing to accuracy in the described curve. The said guide bar 21 is provided witha slot 46 in which is slidably mounted a center block consisting of a plate 47 which rests upon the top of said guide bar and is provided upon the under side with a tongue 48 which is received in the slot 46 of the lguide bar. One lend 49'of the plate 47 is broadened and rounded in circular form and screw 36 and provided with graduations 37.Y

furnished with an offset 40 shown in Fig. 9

49 is a hole 52 through which is passed from.

the under side a pivot screw 53 having a thumb nut 54 and kept in adjusted position by a lock pin 55. The lower face of the nut is of less diameter than the plate end 49 thus allowing the graduations to be easily read when the nut is in place. The head of the pivot screw is in the form of a plate 55a carrying a box or sleeve 56 apertured to receive' a rectangular arm 57 which is furnished with graduations 58 and locked in the sleeve by a set screw 59. The distal end of the said arm is pivoted at 60 tothe end of a companion arm 61 the other end of which is received in 'a suitable aperture in the said rectangular box 31 which is formed integral with the pivot post 30, previously described, and is adjustably held therein by a set screw 62.

rl`he guide bar 21 may be used in two po-v sitions shown in full and dotted lines, respectively, in Fig. 2. To change from one position to the other it is necessary to remove the sectional bar 23 and release the thumb screw 24, upon doing which the said bar can be swung on the center 24 to either of the indicated positions. A clip or box 63 is secured to one end of the guide bar, Vand when the latter is turned to its position parallel to the connecting bar, as shown in dotted lines in Fig. 2, saidbox forms a socket rfor the reception of the inner end oil the rod 23, which is now replaced and xed by its -set screws to form a support as before. The upper margin of the sleeve 32 is provided with graduations 64 and an index mark 65 is impressed upon the extension 29. One side of the bar 21 is furnished with graduations 66 to lacilitate the location of the slide block therein.

The method of using my improved instrument for tracing curves is very simple and readily understood so that it can be operated by one not skilled in the use ot' instruments otl precision. The apparatus having been set up in the manner shown and the center of the curve to be'described having been determined, the instrument is moved until a vertical line through the axis ot' the pivot screw 53 will coincide with the selected location for the curve center. This pivot screw may be termed the master center, for it governs the movements of the levers, locates the centers of the curves, determines the angle ol" inclination of axes, both major and minor, and is the point to which all the most important mechanical movements are referred. The operator impels the tracer by turning the thumb nut 54 with one hand while the lel to the connecting bar 2G.

other is applied to the pencil holder or slide block. The mechanical movements are governed chieiiy by the hand that grasps the nut 54, the force at the block or stylus being only applied in passing the dead center which occur when the slide 27 is at the median line. When the pen illustrated in Fig. 10 is employed the swivel cap 44 is held between the lingers and rotated slightly as the pen travels the object being to keep the lat of the nib tangent to the curve throughout its course in order to get the best results.

In Fig. 2 the tracing bar is shown paral- T he instrument is in a position to describe an ellipse, the major axis of which will be at a right angle to the initial direction of said bars 20 and 35, the axis ot' the pivot post and that of the stylus being at the opposite extremities or the minor axis. Under these conditions the manipulation of the mechanism and the movement would be as follows: We

will suppose the thumb nut to be rotated clock-wise by one hand, the arm 57 will move the center 60 in the same direction circumferentially about the main center 53, and the arm 61 will make traction upon the slide 27 causing it to travel towards the main ce'nter upon its slide-way, the rod 20. The stylus will travel in an opposite direction about its center 30 and when this center has arrived beneath the center 53, the several bars 35, 57 and 61 will lie in the same vertical plane coincident with the major axis of the ellipse. Thus a fourth part of the curve will vhave been described. By further manipulation of the thumb nut and the tracer the slide will be carried on beyond the median line and the movements will continue until another fourth will have been completed.. The several movable arms will again lie parallel with the connecting bar and the pencil will be found to 'have changed places with the pivot point. A continuation of the operation will carry the stylus through the remaining half of the iigures. Thus in trac-ing` ellipses the center 60 will always travel in a circle about the master center, the center 30 describe a right line, and the stylus will move in a true elliptical path and in a direction inverse to that of the center 60.

To change the direction of the axes of the ellipse it is only necessary as the preliminary step, to loosen the screw 33 and-swing the tracing bar around its center to the desired location, it being understood that the major axis will lie at a right angle to a line intersecting the pencil and the main center.

To draw cycloids and epicycloidal curves it is necessary that the guide bar 21 be in the position shown in full lines in Fig. 2. To describe a cycloidal curve the slide 47 is moved to some point a, shown in dotted lines, the slide center moved to a point b.

yalso making but half a turn.

When thetracing bar 37 coincides with the -bar 61, the point c, must lie equi-distant from the tracing point d and the slide center b. Operating the thumb nut 54 and the tracing bar, as before explained, will drive the tracer in an epicycloidal path.

In order to trace a circle the slide 27 is brought to the median line andthe set screw 28EL tightened when the aXes of the centers 53 and 8() coincide, so as to prevent any sliding movement of the center 3() during the operation of tracing the circle. The pencil having been located at the radial distance from the coincident centers7 the operation of the thumb screw will carry the tracer circum'ferentially in a true circle the center of the circle coinciding with the master center. The instrument will describe a theoretically straight line, and the adjustments will permit of such an arrangement as will result in the projection upon the prepared surface of a theoretical point.

To describe a right line the pencil holder shown in Figs. 8 and 9, is substituted for the straight form, and this is brought into apposition with the slide 27 so that the aXes of the slide-center and that of the pencil will coincide. the main center will now cause the slide to move upon its guide rod 20 and as the pencil point is coincident with the center 30, which always moves in a right line, the resulting delineation. will be a straight line subject of course to the minute errorsincident to .all mechanical and physical contrivances. It will be noted that the center 30 always revolves, and in this case the pencil will partake of this movement making one half of a revolution in traveling from the initial point to the limitation of its path, the thumb nut It' the turn were completed, or if made in a reverse direction the pencil will make a retrograde movement over the line previously traced.

To project a point upon the paper or table the centers 38 and 80 are brought into-coincidence as if for tracing aicircle, the centers thus combined then located beneath the Amain, or master center, and the slide 28 locked upon its bar by the set screw 28a. The rotation of' the rthumb screw will then cause the center 30 to rotateand the Atracer which coinc des therewith will revolve in unison with said center 30 and as it has no radial movement the tracer will yinscribe a point or dot coincident with the mechanical, and theoretically with the mathematical center.

. The function of the graduations 50 at the master center is to determine the angular position of the axes of any traced curve, and for describing a given portion of a figure.

rlhe vertical adjustability of the standards will be found very useful in many cases and Rotation of the thumb screw at especially when the center of the curve is -located adjacent to a margin of the drafting board upon which tracings are commonly made. Under such circumstances one support may be placed upon the board or paper, and the base of the other can rest upon the table or bench beside the board and the post adjusted to the paperheight to level the connecting bars.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

1. An apparatus for the purpose specified, including a pivoted slideway, an operating member mounted in said slide-way, a slide 'adapted to be reciprocated in a right line, a

tracingbar attached to said slide and adapted 'to be adjusted circumferentially, and operativemeans connecting the slide with said member.

2. 'An yapparatus for the purpose specified including supports, .a sliding member adapt? ed to be reciprocated in a right line, a tracing bar pivotally attached to the said sliding member, an operating member, means for sliding said operating lmember upon its support and means for simultaneously reciproeating said sliding member and rotating said tracing bar upon its pivot.

3. yAn apparatus for the purpose specified, including adjustable standards, means connecting the standards, a slidable member adapted to be reciprocated in a right line, a tracing member pivotally connected with said slidable member, an operating member mounted upon -a slide, means for adjusting the operating member on said slide, said operating member being adapted to simultaneously.reciprocate said sliding member and rotate the said tracing bar upon its center.

4. An apparatus for the purpose specified, including adjustablestandards, a plurality of bars connecting the standards, a slide adapted to reciprocate upon one of saidbars, an operating member mounted upon a pivoted slide frame means foradjusting said slide frame upon its pivot,means for adjust ing said operating member upon its slideframe, operative connection between said member and said slide, and a tracing bar pivotally connected with said slide and adapted to be rotated upon its" pivot synchronously with the reciprocation of said slide.

5. An apparatus for the purpose specified, including adjustable standards, a'plurality of adjustable bars connecting the standards, a slide adapted to reciprocate upon one of said bars, an operating member adapted to move said slide longitudinally, means for iiXing said slide in' selected positions upon its way, a tracing bar pivotally connected with the slide and adapted to be rotated upon vits pivot s ynchronously with the movement of said slide, and means for adjusting said tracing bar circumferentially about its pivot.

`6. -An apparatus for describing regular` and irregular curves, including a centrally` located operating member, a sliding member, a tracing bar pivotally mounted in said sliding member, an arm adjustably iixed to said operating member, and a lever connected to the pivot of said tracing bar and having pivotal connection with said arm.

'7. An apparatus for describing regular and irregular curves, including a centrally located rotatable operating` member, a slide for saidmember, said slide adapted to swing upon a pivot a slidable member carrying a pivotally mounted tracing bar and means for reciprocating said sliding member by the rotation of said operating member.

8. An apparatus for describing geometrical gures, including a lever centrally pivoted, means for rotating said lever about its pivot, a slide-way for said pivot, means for adjusting said pivot in said slide-way a slide adapted to be moved in a right line in a path intersecting the prolongation of the axis of said pivot, and a tracing bar pivoted in said slide and having an arm pivotally connected with the free end of said centrally pivoted lever.

9. An apparatus for describing' geometrical gures including aplurality of adjustable supports, adjustable bars connecting said supports, a slotted guide bar, a block adapted to slide in said guide bar, a lever pivoted to said blocks, means for manually rotating.

said lever, a slide adapted to move in a right line, a tracing member pivoted in said slide, an arm fixed to the pivot in said slide and having pivotal connection with the said lever.

10. An apparatus for describing curves including a movable focal center, a slide way for said focal point, a lever adjustably mounted to rotate on said focal center, a sliding center, a graduated tracing bar adjustably mounted in said sliding center, and an adjustable arm pivotally connecting said tracing bar with said lever, and means for varying the angle between said tracing bar and said adjustable arm.

11.' An apparatus for describing curves, including a movable focal center, a lever pivoted at said focal center and provided with graduations, a tracing bar pivotally mounted, and means for moving said tracing bar upon its pivot, said means consisting of a graduated arm adjustably secured to said pivot and having a pivotal connection with the said lever.

12. An apparatus for describing geomet rical figures, including duplicate adjustable standards, a slotted adjustable guide-bar supported upon said standards, a center adapted to slide in said guide bar, a graduated lever pivoted at said center and Vadapted to be manually revolved on its pivot, a slide adapted to be vmoved in a linear direction, and having an adjustable graduated tracing bar pivoted thereto, an arm pivotally connecting said tracing bar with said graduated center adapted to slide in the guide bar, said guide-bar having graduations for indicating the longitudinal adjustment of said center, a graduated lever pivoted at said center and adapted to be manually revolved upon its pivot, a slide adapted to be impelled in a linear path and carrying a graduated adjustable tracing bar pivoted thereto, an arm pivotally connecting said tracing bar with said graduated lever, means for varying the angle between the tracing bar and said arm, and an adjustable stylus mounted upon the said tracing arm, and provided with an offset.

14. An apparatus for describing geometrical iigures, including a slottedadjustable guide bar, a center adapted to slide in said bar, and having a rotatable axis mounted therein, said center being provided with graduations for determining the angular position of its axial attachments, a graduated lever adjustably mounted upon said axis, a slidable center adapted to move in a linear path, a pivot post mounted at said slidable center and provided with an adjustable graduated arm having pivotal connection with said graduated lever, a tracing bar adjustably attached to said pivot post and adapted to be adjusted circumferentially about its. center, and an adjustable stylus mounted upon said tracing bar and adapted to be placed so that its axis will coincide with the axis of said pivot post.

15. An apparatus for describing geometrical gures, including a foldable guide-bar, a center adapted to slide in said bar and carrying an axially mounted pivot provided with' graduations for determining its angular position, a graduated lever carried upon said axis, a slidable center adapted to move in a linear path, means for securing said slidable center from lateral movement, a pivot post mounted in said slidable center, an adjustable graduated arm attached to said post and having pivotal connection with said graduated lever, a tracing bar detachably connected to said post and adapted to be adjusted circumferentially about its center of revolution and an adjustable stylus carried on said tracing bar.

16. An apparatus for tracing geometrical figures, including a focal center, means for sliding said center in a horizontal plane, a

sliding center adapted to be moved n a linear 1 n testirnony whereof I affix my signature petll, a* tracing mellberadaptdtolbelced in the presence of two Witnesses, so t "atts "w'svif-v corres "on" Wit it" e-aXS Y f Qf Seid Sheng Center., -andlean-S fprbrigmg f v u -K HENRY LOOYER' 5 the axes of said tracing `'member and -selifd '111g Witnesses:

sliding center into coincidence with the s'd FREDERICK BENJAMIN, focal center. f T.-M. PoYN'roN. 

